Extension-ladder.



No. 783,292. 'PATENTED FEB. 21, 1905. F. R. LEWIS.

EXTENSION LADDER.

APPLICATION FILED JAN 21 1904 Elwuewifoz friend R. 136M C1 iter/"M10.

UNTTED STATES Patented February 21, 1905.

PATENT EETEE.

FRIEND R. LEWIS, OF SCRANTON, PENNSYLVANIA, ASSIGNOR OF ONE-HALF TOFREDERICK T. BARROWMAN, OF SGRANTON, PENNSYLVANIA.

EXTENSION-LADDER.

SPECIFICATION forming part of Letters Patent No. 783,292, dated February21, 1905.

Application filed January 21, 1904. Serial No. 90,00

To a who/n it may concern.-

Be it known that I, FRIEND R. LEWIS, a citizen of the United States,residing at Scranton,

in the county of Lackawanna and State of Pennsylvania, have inventedcertain new and useful Improvements in Extension-Ladders; and I dohereby declare the following to bea full, clear, and exact descriptionof the invention, such as will enable others skilled in the art to whichit appertains to make and use the same.

This invention relates to improvements in ladders, and particularly toextension-ladders which are capable of adjustment, so as to reachvarious heights.

The invention consists in an extension-ladder provided withladder-sections, lockingpawls carried by the ladder-sections, andreleasing-cams used in connection therewith and carried by one of theladder-sections.

The invention also consists in an extension step-ladder formed withtelescoping laddersections and telescoping leg or supporting sections,the said ladder and leg sections being provided with locking-pawls andreleasepawls cooperating with each other.

The invention further consists in certain other novel constructions andarrangements of parts, as will be more fully described and claimed.

In the accompanying drawings, Figure 1 is a central verticallongitudinal section through an extension-ladder constructed inaccordance with the present invention. Fig. 2 is an enlarged detail viewshowing the ladder-sec tions in such a position that the release-camswill carry the locking and supporting pawls past the shoulders whichthey normally engage. Fig. 3 is a similar view showing the position ofthe cam as it lifts the locking and supporting pawl. Fig. 4 is a detailperspective view of one of the locking and supporting pawls, the bracketcarrying the said pawl being also shown.

The present invention is designed to supply a sectional extension-ladderwhich may be raised and lowered and altered in length at will by merelyputting it in proper position and raising the sections sufficicntly tolock or release, as the case may be, the supportingpawls of theladder-sections.

While the invention is applicable to ladders of all kinds, I haveillustrated it as applied to a step-ladder and will proceed to describethe novel features of my invention referring to the illustration.

1 in the drawings represents a ladder the step or ladder portion ofwhich is formed of a plurality of sections, as 2 and 3. Section legs orsupports 4 and 5 are also provided and connected, by means of hinges, tothe upper end of the step portion. The ladder-sections 2 and 3 may beprovided with rungs or steps, as 6 or 7 of any usual or ordinary type,as shown in Fig. 1. The lower ladder-section 3 is adapted to slide uponthe upper laddersection 2 and is provided with guide-plates 8, whichengage the sides of the upper laddersection 2. The inner ends of theseguideplates are turned inwardly, so as to engage the under edge of theupper ladder-section and prevent the separation of the laddersections,while permitting of their longitudinal movement with respect to eachother. The upper section 2 is also provided with guideplates, as 9, bentinwardly at their outer ends, so as to engage the sides of the lowerladder-sections in the same manner as just described with respect to theplates 8. One of the ladder-sections, preferably the upper one, 2, isformed with notched or shouldered portions 10, which are engaged bylocking and supporting pawls 11, carried by the other ladder-section, 3.The pawls 11 are pivotally secured to each side of the laddersection 3at their lower ends, and their upper ends are free to rest against theouter edge of the upper ladder-section 2. When the ladder-section 3 isdrawn outwardly a sufficient distance to permit the pawl 11 to dropbeneath one of the shoulders 10, it will lock the sections againstmovement in one direction and accomplish the extension of the ladder, asshown in Fig. 1. The sides of the ladder-section 2 below the shoulders10 are beveled outwardly, so that when the ladder section 3 is furtherpulled outwardly the pawl 11 will again ride upon the edge of theupperbe pivoted directly to the side of the laddersection, I preferablyuse a bracket 14 for securing the pawl in position. This bracket 14 maybe made in a simple and yet strong manner by folding a piece of metalupon itself, as shown in Fig. 4:, one end of the said piece beingoffset, as at 15, to provide a suitable space between the ends of themetal piece to receive one end of the pawl 11. A rivet or pivot-pin 16is passed through the ends of the brackets and the end of the pawl forpivotally securing the pawl in place. The bracket is then secured totheinner face of the side bar of said ladder-section, as clearlyillustrated in the drawings.

It will be evident that in order to extend the length of the ladder itis only necessary to pull the ladder-sections apart-until the pawlengages the desired notch or shoulder 10. It is also desirable to soconstruct the ladder that the pawl can be readily disengaged from anyone of the shoulders 10 and the secto a suitable extent upon each other.

tions so folded as to shorten the ladder. I accomplish this purpose in asimple manner by providing one of the ladder-sections, as 2, withreleasecams or pawls 17, which are pivoted, as 'at'18, to the side bars of saidsection at points adjacent to the shoulders 10. The release-cams 18 areelongated in shape and so poised upon their pivots that when the ladderis in an upright position the said release-cams will lie approximatelyin a horizontal position. Each release-cam is preferably pointed at oneend, as 19, and adjacent to said end is formed with a lifting-shoulder20, which engages the locking and supporting pawl 11 for lifting it overthe space beneath the shoulder 10. \Nhen the ladder is to be reduced inlength, the sections are pulled apart sufliciently to draw the pawls 11below the release-cams 17, the said cams then assuming the position withrespect to said pawls shown in Fig. 2. The ladder-sections are nextforced together, when the pawl 11 will be engaged by theliftingshoulders 20 of the releasing-cam, and carried past the-shoulder10, as illustrated in Fig 3. The releasing-cams 17 act automatically tocontrol the movement of the pawls 11, so that the ladder may be extendedor reduced in length at will by merely sliding the sections W hen theladdersections are extended only far enough for the pawls I1 to dropbeneath the shoulders 10, as shown in Fig. 1, the releasecams 17 will bemerely pushed to one side. When, however, the sections are separatedsufficiently for the free ends of the pawls 11 to pass the points of therelease-cams, the sections may then be collapsed or forced together, thesaid cams carrying the pawls over the shoulders 10.

The leg or standard supporting portions 4 and 5 of the step-ladder areconstructed in a similar manner to the step-sections 2 and 3,beingcapable of sliding upon each other and being guided in their movement bymeans of plates 21 and 22. These supporting sections or legs are alsoprovided with locking and supporting pawls, as 23, which are pivoted toone section and adapted to engage shoulders 24 upon the other section.Brackets 25 may also be used for pivotally supporting these pawls inposition. Releasingearns 26 are pivoted to one of the leg-sections ofthe stepladder, acting in conjunction with the pawls I 23, so that saidleg-sections may be extended or reduced in lengthat will and in the samemanner as described in the step-sections of the ladder.

When the invention is applied to a step-ladder, the leg-sections areconnected with the step-sections by pivoted links 2-7 for limiting theextent to which the ladder may be spread or opened. sections 2 and 3 maybe strengthened by steel rods 28, which are arranged beneath the stepsand extend from one side bar of the laddersection to the other sidethereof.

It will be evident that the pawls 11 may be pivoted directly to the sidebars of the ladder-sections and of the leg-sections without the use ofbrackets 14: and without departing in the least from the spirit of theinvention. It will also be evident that other minor changes may be madein putting the invention into practical form all within the scope of thesaid invention. The construction of the parts, while efiective for thedesired purpose, is simple and. yet not likely to getout of order. Therelease-cams can be made in various shapes without altering theinvention, it being only necessary to suspend them so that when it isdesired to fold the ladder the said cams will be capable of lifting thelocking and supporting pawls over the recesses at the shoulders 10.

Having now described and ascertained the nature of my said invention,what I claim, and desire to secure by Letters Patent, is

1. An extension-ladder comprising laddersections, a supporting andlocking pawl car- 'ried by some of said sections, means formed in theother sections for engaging said pawls, and releasing-cams carried bysaid pawl-engaging sections.

2. An extension-ladder comprising sliding ladder-sections, locking andsupporting pawls carried by one section, supporting-shoulders formed inthe edge of the other section for If desired, the steps of the ladder- 5engaging said pawls and pivotally-mounted releasing-cams carried by thesaid section provided with shoulders.

13. An extension-ladder made up of sliding sections, pivoted pawlscarried by one of said sections,pawl-engaging means assembled with theother sections, and gravity-actuated releasing-cams carried by saidsection provided with pawl-engaging means and cooperating with saidpawls.

4. An extension-ladder comprising laddersections and leg-sections,locking-pawls carried by some of the ladder and leg sections,pawlengaging means assembled with the other ladder and leg sections, andreleasing-cams carried by said ladder and leg sections provided withpawl-engaging means.

5. An extension-ladder comprising sliding sections, locking-pawlscarried by some of said sections, pawl-engaging means assembled with theother sections, pivoted, releasingcams carried by said sections providedwith pawl-engaging means and formed with lifting shoulders, saidshoulders lifting the pawls out of locking position when the sectionsare to be telescoped.

6. An extension-ladder com-prising telescoping sections,pivotally-mounted locking and supporting pawls carried by some of saidsections, means formed in the other sections for engaging the same, andbrackets for pivotally supporting said pawls upon said sections.

7. An extension-ladder comprising sliding sections, means for holdingsaid sections movably together, supporting-pawls carried by some of saidsections, brackets for securing the pawls to saidsections. each bracketcomprising a single piece of metal folded upon itself and spread apartat one end, and means for pivotally securing a pawl between said ends.

8. An extension-ladder comprising slidin ladder-sections, said sectionsprovided with cut-out portions formed upon their meeting edges, lockingand supporting pawls carried by one section and normally engaging saidcutout portions, and gravity-actuated releasingcams assembled with theother section and cooperating with said pawls.

9. An extension-ladder comprising a plurality of slidable sections, eachsection having a shoulder formed in one edge thereof, locking .meansmovably mounted Within said shouldered portions, and means for movingsaid locking means.

10. An extension-ladder comprising sliding sections, locking andsupporting pawls carried by one section, each of said pawls comprising abody portion, an integral extension projecting at right angles from oneend of said body portion, means formed upon the other section forengaging and retaining said pawls in a locked position, and releasingmeans for actu- I ating said pawls carried by said pawl-engagingsections.

11. An extension-ladder comprising a plurality of sliding sections, eachsection provided with recessed portions formed upon one edge, pawlsmounted upon some of said sections and engaging said recessed portionscomprising a support, a body portion pivotally mounted on said support,an integral extension projecting from the outer edge of said bodyportion and at right angles thereto, said extension normally engagingsaid recessed portions, and automatically-actuated pawl-releasing meansmounted upon the other sections. s

In testimony whereof I hereunto afiixmy signature in presence of twowitnesses.

FRIEND R. LEWIS.

Witnesses:

W. W. BAYLoR, WV. S. ROBINSON

